Exploring the Sodium‐Storage Mechanism of Nanosized Disodium Rhodizonate as the Anode Active Material

Abstract

Nanosized disodium rhodizonate (Na2C6O6, NCO) prepared by antisolvent crystallization is tested as an organic anode material for sodium‐ion batteries (SIBs). A reversible capacity of 230 mAh g−1 combined with an excellent capacity retention of ≈85% after 1000 cycles versus Na/Na+ is demonstrated in a NaPF6‐DME electrolyte. Such a promising electrochemical performance is achieved by the synergy of the NCO particle nanosizing, and the formation of a thin, but stable and Na+‐permeable solid electrolyte interface layer that builds‐up readily in the NaPF6‐1,2‐dimethoxyethane electrolyte. The feasibility of the nanosized NCO anode for SIBs is also confirmed in a full sodium‐ion cell versus Na3V2(PO4)3 cathode, and the discharge potential is as high as 2.0 V suggesting a promising energy density.